The present invention relates to a solid-state imaging device, a method of manufacturing the same, and an electronic apparatus.
Solid-state imaging devices are broadly classified into two representative kinds of solid-state imaging devices of a CCD (Charge Coupled Device) image sensor and a CMOS (Complementary Metal Oxide Semiconductor) image sensor. In recent years, the size of a pixel has decreased and the number of photons incident on a unit pixel has decreased in CCD image sensors and CMOS image sensors. As a result, sensitivity deteriorates the solid-state image sensor and there is a decrease in the signal to noise ratio (S/N).
In widely used pixel arrangements where red, green, and blue pixels are arranged on planar surface, such as the Bayer arrangement that uses primary color filters, green and blue light does not penetrate the color filter in red pixels and is not used in photoelectric conversion. Therefore, sensitivity of the image sensor may decrease. Moreover, when a color signal is formed by executing an interpolation process between pixels, false color may arise.
In order to solve these problems, Japanese Unexamined Patent Application Publication No. 2007-12796 discloses a solid-state imaging device in which green, blue, and red photoelectric conversion units are laminated in a depth direction in the same pixel. In this solid-state imaging device, a blue photodiode (photoelectric conversion unit) and a red photodiode (photoelectric conversion unit) are formed in the depth direction in a silicon substrate. In addition, the solid-state imaging device includes an organic photoelectric conversion unit in which a green organic photoelectric conversion layer is interposed between electrodes and formed on the upper layer of the front surface of the silicon substrate on the side of a light-sensing portion with a wiring layer interposed between the photoelectric conversion layer and the substrate. According to the configuration disclosed in Japanese Unexamined Patent Application Publication No. 2007-12796, light loss does not occur in the color filter and the sensitivity of the solid-state imaging device is improved. Moreover, since the interpolation process is not performed between pixels, false color does not occur.
Japanese Unexamined Patent Application Publication No. 2008-258474 discloses a back-illuminated CMOS image sensor including color filters, a photoelectric conversion unit with photodiodes laminated in a depth direction, and an organic photoelectric conversion layer. The solid-state imaging device disclosed in Japanese Unexamined Patent Application Publication No. 2008-258474 includes color filters arranged in a yellow and cyan check pattern. The photoelectric conversion unit formed by red and blue photodiodes is disposed in a manner that coordinates with the yellow and cyan filters. Moreover, an organic photoelectric conversion unit is disposed in the upper layer of each photodiode. In this solid-state imaging device, the organic photoelectric conversion unit is sensitive to green light, the photodiode of the yellow filter is sensitive to red light, and the photodiode of the cyan filter is sensitive to blue light.